Unlocked Sony Xperia NXT smartphones now on sale in U.S.

Prices range from $299 to $559; all three models upgradeable to Android 4.0

 Sony began sales today of unlocked versions of its xperia NXT series of smartphones in the U.S., with prices ranging from $299.99 to $559.99.

The three Android 2.3 smartphones -- the Xperia S, Xperia P and Xperia U -- all work over HSPA and GSM networks, meaning they will function over AT&T and T-Mobile USA network channels.

Sony said all three phones are upgradeable to Android 4.0, known as Ice Cream Sandwich (ICS). Sony said in May that the Xperia S was due for ICS at the end of June, with the other two following later in the year.

The Xperia S will sell for $559.99 unlocked; the Xperia P is $479.99 unlocked; and the Xperia U will be $299.99 unlocked. They are now being sold at U.S. Sony retail stores and on sony.com/NXT and at Newegg.com and other online retailers that Sony didn't name.

Sony didn't explain why it offered the phones unlocked. It is unusual for phone manufacturers to market unlocked phones separate from the subsidized prices offered by the carriers, although Google has done so with its Nexus line. Subsidized smartphones are typically sold by U.S. carriers at $200 to $250 with two-year service commitments.

Some buyers of unlocked phones in the U.S. will set up a data plan with a carrier along with an Internet voice-calling app that makes voice calls free or at an inexpensive rate. The carriers offer several pre-paid data plans that don't require a long-term commitment.

In its statement, Sony described the smartphones as "incorporating the best of Sony technology and premium entertainment" with easy connectivity. The three all have a "transparent element," a band of light that encircles the base of each phone that illuminates when receiving calls, texts and other notifications. That band also integrates antenna components that aren't visible.

Sony introduced the Xperia P and Xperia U in February, after announcing the Xperia S in January. The Experia S went on sale in Spain in February about the time Sony completed its buy out of Sony Ericsson.

The Xperia S comes in black or white with a 4.3-in. HD screen with 1280-x-720-pixel resolution, and a 12-megapixel rear-facing camera. It runs a 1.5 GHz Qualcomm MSM8260 Dual Core processor and is NFC-ready. It has 1GB of RAM and up to 32 GB of internal storage.

The mid-price Xperia P comes in silver, red or black and has a 4-in. display with 960-x-540-pixel resolution and an 8-megapixel rear-facing camera. It runs on a 1GHz STE U8500 dual-core processor and is NFC-ready. It comes with 1GB RAM with up to 16 GB of internal storage.

The low-price Xperia U comes in black or white and has a 3.5-in. screen, with 854-x-480-pixel resolution, and a 5-megapixel rear camera. It also has a 1GHz STE U8500 dual-core processor, and 512MB RAM with up to 8GB of internal storage.